This disclosure is based upon, and claims priority from French Application No. 98/12386, filed on Oct. 2, 1998 and International Application No. PCT/FR99/02246, filed Sep. 22, 1999, which was published on Apr. 13, 2000 in a language other than English, the contents of which are incorporated herein by reference.
The invention relates to a smart card or xe2x80x9cchip cardxe2x80x9d provided with inhibiting means.
The invention relates more particularly to a contactless smart card comprising a card body, an antenna and, connected to the connection terminals of said antenna, an integrated-circuit chip. Such cards are designed to perform: various debit operations in public-transport vehicles, and in particular in subways, i.e. underground railways, buses, or trains; banking operations; telephone calls; or various identification operations. Such operations are performed by means of electromagnetic coupling between the card and receiver or reader equipment. The coupling can be implemented in read mode or in read/write mode.
In a particularly common application, such smart cards, be they provided with contacts or be they contactless, are used as means for paying for a service. Each time the corresponding service is used, at least one unit of value is decremented from the initial stock of units of value loaded in the memory of the smart card. Such applications are to be found, for example, in telephone cards and in photocopier cards. Such a smart cards thus initially contains in its memory a given number of units of value corresponding to the maximum credit.
In most applications in which the smart card is used as payment means, the card used is of the type having contacts and in which conductive tracks are connected to the integrated-circuit chip, and make it possible for the card to be electrically connected to a reader.
In which case, in order to guarantee to the user that the card purchased by him or her has the maximum number of units of value, it is necessary merely to wrap the card in a sealed jacket, e.g. in the form of cellophane wrapping, thereby preventing any electrical contact with the conductive tracks.
When the card is a contactless card, that solution is not satisfactory. The cellophane jacket cannot prevent interchange of information that takes place remotely between the card and a reader. Therefore, when the card is a contactless smart card, a sealed jacket cannot guarantee that the card has not been used previously.
An object of the invention is therefore to provide a novel smart card design in which inhibiting means are provided that make it possible to prevent any fraudulent use of the card prior to it being used for the first time by an authorized user.
To this end, the invention provides a contactless smart card comprising a card body, an antenna and, connected to the connection terminals of said antenna, an integrated-circuit chip, said smart card being characterized in that the connection terminals of the antenna are further connected to conductive through holes opening out on the surface of the card, and in that a junction based on an electrically conductive substance, and designed to be removed by being scratched off before the card is used for the first time, is disposed flush with the surface of the card, and interconnects the conductive through holes.
According to another characteristic of the invention, the card further comprises a two-faced electronics module received in a cavity provided in the card body, the antenna and the integrated-circuit chip being supported by a first face of said electronics module, the conductive through holes connected to the connection terminals of the antenna being provided through the thickness of said module, and the junction interconnecting the conductive through holes being provided on the second face of said module, said second face being flush with the surface of the card.
According to yet another characteristic of the invention, the antenna extends throughout the plane of the card body, the antenna and the integrated-circuit chip are embedded in the card body, and the conductive through holes connected to the connection terminals of the antenna are provided through the thickness of the card body so that they open out on its surface.
According to yet another characteristic of the invention, the electrically conductive substance used to form the junction is an ink based on epoxy charged with silver particles or with carbon.